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From: Joerg Roedel <joro@8bytes.org>
To: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	Joerg Roedel <jroedel@suse.de>
Subject: Re: [PATCH 2/3] x86, swiotlb: Try coherent allocations with __GFP_NOWARN
Date: Mon, 26 Jan 2015 12:54:08 +0100	[thread overview]
Message-ID: <20150126115408.GE30345@8bytes.org> (raw)
In-Reply-To: <20150126032236.GN2461@dhcp-16-105.nay.redhat.com>

On Mon, Jan 26, 2015 at 11:22:36AM +0800, Baoquan He wrote:
> > Ok, so this practically does all allocations __GFP_NOWARN now. Shouldn't
> > you be doing this before swiotlb_alloc_coherent() and not before
> > dma_generic_alloc_coherent()?
> 
> I think this patch mainly suppress warning from buddy allocation
> failure because it tried buddy allocation several times before the final
> try of bounce buffer allocation. Buddy allocation failure will call
> dump_stack.

Yes, exactly. The default low-memory available to the page-allocator
with crashkernel=high is 8MB. This is up pretty fast and then we start
to get warnings, even when there is still memory left in the swiotlb
space. The __GFP_WARN is there to suppress the warnings from the
page-allocator, so it has to be set before it is called.


	Joerg


  reply	other threads:[~2015-01-26 11:54 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-06 14:51 [PATCH 0/3 v2] Fix kdump failures with crashkernel=high Joerg Roedel
2015-01-06 14:51 ` [PATCH 1/3] swiotlb: Warn on allocation failure in swiotlb_alloc_coherent Joerg Roedel
2015-01-23 17:04   ` Borislav Petkov
2015-01-26 11:49     ` Joerg Roedel
2015-01-06 14:51 ` [PATCH 2/3] x86, swiotlb: Try coherent allocations with __GFP_NOWARN Joerg Roedel
2015-01-23 17:03   ` Borislav Petkov
2015-01-26  3:22     ` Baoquan He
2015-01-26 11:54       ` Joerg Roedel [this message]
2015-01-06 14:51 ` [PATCH 3/3] x86, crash: Allocate enough low-mem when crashkernel=high Joerg Roedel
2015-01-23  8:44   ` Baoquan He
2015-01-26 12:07     ` Joerg Roedel
2015-02-01  8:41       ` Baoquan He
2015-02-04 14:10         ` Joerg Roedel
2015-02-09 12:20           ` Joerg Roedel
2015-02-13 15:34             ` Baoquan He
2015-02-13 22:28               ` Joerg Roedel
2015-02-14 11:44                 ` Baoquan He
2015-01-23 17:02   ` Borislav Petkov
2015-01-26 12:11     ` Joerg Roedel
2015-01-26 12:20       ` Borislav Petkov
2015-01-26 12:40         ` Joerg Roedel
2015-01-26 12:45           ` Borislav Petkov
2015-01-14 13:35 ` [PATCH 0/3 v2] Fix kdump failures with crashkernel=high Joerg Roedel
2015-01-19 19:26 ` Borislav Petkov
2015-02-14 10:58 ` Baoquan He
2015-02-14 16:11   ` Joerg Roedel
2015-06-02  8:54     ` Baoquan He
2015-06-02  9:08       ` Joerg Roedel
  -- strict thread matches above, loose matches on Subject: below --
2015-06-05 10:29 [PATCH 0/3 v3] " Joerg Roedel
2015-06-05 10:30 ` [PATCH 2/3] x86, swiotlb: Try coherent allocations with __GFP_NOWARN Joerg Roedel
2014-11-28 11:29 [PATCH 0/3] Fix kdump failures with crashkernel=high Joerg Roedel
2014-11-28 11:29 ` [PATCH 2/3] x86, swiotlb: Try coherent allocations with __GFP_NOWARN Joerg Roedel
2014-12-01 20:28   ` Konrad Rzeszutek Wilk
2014-12-02 14:45     ` Joerg Roedel
2014-12-02 18:46       ` Konrad Rzeszutek Wilk
2014-12-03 10:27         ` Joerg Roedel

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